Optical lens

ABSTRACT

An optical lens makes object light rays transmit from an object side to an image side on an optical axis and form an image on an image plane. The optical lens comprises a lens group establishing the optical axis, comprising a first lens and a second lens arranged in order from the image side to the object side, wherein the first lens has an image-side surface which is a concave face and has a point of inflection arranged thereon; and a first aperture stop and a second aperture stop separately located on the optical axis. The optical lens meets the thinning tendency.

TECHNICAL FIELD OF THE DISCLOSURE

The present invention relates to an optical lens, and more particularly,to an optical lens equipped with two aperture stops.

BACKGROUND OF THE DISCLOSURE

An optical lens generally has an aperture stop, or even is equipped withan aperture-adjustable stop, that is, the size of aperture of theoptical lens can be automatically or manually adjusted. In aconventional optical lens, the aperture-adjustable stop is disposedwithin the lens system or between any two lenses. This type of opticallens has to provide enough space for accommodating the structuralcomponents or electric control components used to mount theaperture-adjustable stop, and therefore there exists a problem of thistype of optical lens which is unable to be further thinned.

SUMMARY OF THE DISCLOSURE

The objective of the present invention is to provide an optical lens forsolving the problem of a conventional optical lens which is unable to befurther thinned.

To achieve above objective, the present invention provides an opticallens, which makes object light rays transmit from an object side to animage side on an optical axis and form an image on an image plane, saidoptical lens comprising a lens group establishing the optical axis,comprising a first lens and a second lens arranged in order from theimage side to the object side, wherein the first lens has an image-sidesurface which is a concave face and has a point of inflection arrangedthereon and a first aperture stop and a second aperture stop separatelylocated on the optical axis.

In another aspect, the present invention provides an optical lens, whichmakes object light rays transmit from an object side to an image side onan optical axis and form an image on an image plane, said optical lenscomprising a lens group establishing the optical axis, a first aperturestop disposed within the lens group and a second aperture stop disposedat the object side outside the lens group.

The optical lens of the present invention improves the effectiveaperture range. In comparison to the optical lens having an aperturestop with adjustable aperture disposed within the lens group in theconventional skills, the optical lens of the present invention candeploy the aperture stop with adjustable aperture at the outside of thelens group, and therefore the structural components or electric controlcomponents required to be used to mount the aperture-adjustable stop canbe moved to the outside of the lens group, thereby carrying out furtherthinning of the optical lens.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram showing an optical structure inaccordance with a first embodiment of an optical lens of the presentinvention.

FIG. 1B is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the firstembodiment of the present invention in the condition that a firstaperture stop is in an active state and a second aperture stop is in aninactive state.

FIG. 1C is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the firstembodiment of the present invention in the condition that the firstaperture stop is in the inactive state and the second aperture stop isin the active state.

FIG. 1D is a diagram showing polychromatic diffraction modulationtransfer function (MTF) of the optical lens according to the firstembodiment of the present invention in the condition that the firstaperture stop is in the active state and the second aperture stop is inthe inactive state.

FIG. 1E is a diagram showing polychromatic diffraction modulationtransfer function of the optical lens according to the first embodimentof the present invention in the condition that the first aperture stopis in the inactive state and the second aperture stop is in the activestate.

FIG. 2A is a schematic diagram showing an optical structure inaccordance with a second embodiment of an optical lens of the presentinvention.

FIG. 2B is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the secondembodiment of the present invention in the condition that a firstaperture stop is in an active state and a second aperture stop is in aninactive state.

FIG. 2C is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the secondembodiment of the present invention in the condition that the firstaperture stop is in the inactive state and the second aperture stop isin the active state.

FIG. 2D is a diagram showing polychromatic diffraction modulationtransfer function (MTF) of the optical lens according to the secondembodiment of the present invention in the condition that the firstaperture stop is in the active state and the second aperture stop is inthe inactive state.

FIG. 2E is a diagram showing polychromatic diffraction modulationtransfer function of the optical lens according to the second embodimentof the present invention in the condition that the first aperture stopis in the inactive state and the second aperture stop is in the activestate.

FIG. 3A is a schematic diagram showing an optical structure inaccordance with a third embodiment of an optical lens of the presentinvention.

FIG. 3B is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the thirdembodiment of the present invention in the condition that a firstaperture stop is in an active state and a second aperture stop is in aninactive state.

FIG. 3C is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the thirdembodiment of the present invention in the condition that the firstaperture stop is in the inactive state and the second aperture stop isin the active state.

FIG. 3D is a diagram showing polychromatic diffraction modulationtransfer function (MTF) of the optical lens according to the thirdembodiment of the present invention in the condition that the firstaperture stop is in the active state and the second aperture stop is inthe inactive state.

FIG. 3E is a diagram showing polychromatic diffraction modulationtransfer function of the optical lens according to the third embodimentof the present invention in the condition that the first aperture stopis in the inactive state and the second aperture stop is in the activestate.

FIG. 4A is a schematic diagram showing an optical structure inaccordance with a fourth embodiment of an optical lens of the presentinvention.

FIG. 4B is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the fourthembodiment of the present invention in the condition that a firstaperture stop is in an active state and a second aperture stop is in aninactive state.

FIG. 4C is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the fourthembodiment of the present invention in the condition that the firstaperture stop is in the inactive state and the second aperture stop isin the active state.

FIG. 4D is a diagram showing polychromatic diffraction modulationtransfer function (MTF) of the optical lens according to the fourthembodiment of the present invention in the condition that the firstaperture stop is in the active state and the second aperture stop is inthe inactive state.

FIG. 4E is a diagram showing polychromatic diffraction modulationtransfer function of the optical lens according to the fourth embodimentof the present invention in the condition that the first aperture stopis in the inactive state and the second aperture stop is in the activestate.

FIG. 5A is a schematic diagram showing an optical structure inaccordance with a fifth embodiment of an optical lens of the presentinvention.

FIG. 5B is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the fifthembodiment of the present invention in the condition that a firstaperture stop is in an active state and a second aperture stop is in aninactive state.

FIG. 5C is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the fifthembodiment of the present invention in the condition that the firstaperture stop is in the inactive state and the second aperture stop isin the active state.

FIG. 5D is a diagram showing polychromatic diffraction modulationtransfer function (MTF) of the optical lens according to the fifthembodiment of the present invention in the condition that the firstaperture stop is in the active state and the second aperture stop is inthe inactive state.

FIG. 5E is a diagram showing polychromatic diffraction modulationtransfer function of the optical lens according to the fifth embodimentof the present invention in the condition that the first aperture stopis in the inactive state and the second aperture stop is in the activestate.

FIG. 6 is a schematic diagram showing a package structure in accordancewith a first embodiment of an optical lens of the present invention.

FIG. 7 is a schematic diagram showing a package structure in accordancewith a second embodiment of an optical lens of the present invention.

DETAILED DESCRIPTION OF THE DISCLOSURE

To make the above-mentioned and other objectives, features, and effectsof the present invention more easily understood, the present inventionis described in further detail below with reference to the embodimentsin accompanying with the appending drawings.

For simplicity and ease of understanding, the features and/or componentsdescribed in the present invention are illustrated by relative sizeand/or orientation, and however, actual size and/or orientation maydiffer from the illustrated size and/or orientation. For clarity, thesize or relative size of the illustrated features and/or components maybe exaggeratedly enlarged or shrunk. Also, for simplicity and clarity,identical or similar components are indicated by the same referencenumber and descriptions of well-known functions and structures areomitted.

The optical lens provided in the present invention is applicable tovarious image capturing devices equipped with a camera, for example, acell phone, a smart phone, a tablet computer, a netbook, a laptopcomputer, a personal digital assistant (PDA), a handheld or portablecomputer, a smart watch, a smart glasses, a smart wearable device, agame player, a camera, a camcorder, a surveillance apparatus, an IP CAM,an event data recorder (EDR), a car rear view apparatus, and varioussensors.

The basic structure of the optical lens of the present invention isillustrated by FIG. 1A (corresponding to a first embodiment), FIG. 2A(corresponding to a second embodiment), FIG. 3A (corresponding to athird embodiment), FIG. 4A (corresponding to a fourth embodiment), andFIG. 5A (corresponding to a fifth embodiment). The optical lenscomprises a lens group, which establishes an optical axis OA and isarranged along the optical axis OA. Object light rays enter such anoptical system from an object side OBJ of the optical axis OA and forman image on an image plane IP at an image side IMA thereof. The opticallens further comprises a first aperture stop STO1 and a second aperturestop STO2. Preferably, the first aperture stop STO1 is disposed insidethe lens group, that is, between any two lenses of the lens group; andthe second aperture stop STO2 is disposed outside the lens group at theoutside of the object side OBJ of the optical axis OA, that is, at theoutside of a lens of the lens group at the most object side OBJ.

In the illustrated optical lens, the aperture of the optical lens isdefined by the aperture of the second aperture stop STO2 when a smalleraperture is required; the aperture of the optical lens is defined by theaperture of the first aperture stop STO1 when a larger aperture isrequired. For instance, when a smaller aperture is required, decreasethe aperture of the second aperture stop STO2 to be at least less thanthe aperture of the first aperture stop STO1. Since the aperture of thefirst aperture stop STO1 is greater than that of the second aperturestop STO2, the first aperture stop STO1 ceases to be effective due tothe evolution of light path and is thus in an inactive state. Meanwhile,the second aperture stop STO2 is in an active state, and therefore thesmaller aperture of the optical lens is now defined by the aperture ofthe second aperture stop STO2. When a larger aperture is required,increase the aperture of the second aperture stop STO2 to be at leastgreater than the aperture of the first aperture stop STO1. Meanwhile,the second aperture stop STO2 ceases to be effective due to theevolution of light path and is thus in an inactive state. The firstaperture stop STO1 is in an active state, and therefore the aperture ofthe optical lens is now defined by the first aperture stop STO1. Theafore-described example is illustrated by taking the second aperturestop STO2 as an aperture stop with adjustable aperture for example.However, the following examples can also achieve above effects, that is,the first aperture stop STO1 is an aperture stop with adjustableaperture or both of the first aperture stop STO1 and the second aperturestop STO2 are adjustable in aperture. However, the second aperture stopSTO2 that is adjustable in aperture has an advantage. That is, theaperture stop with adjustable aperture can be deployed at the outside ofthe lens at the most object side. Since there has more room foraccommodating an aperture adjusting device in this configuration, thesize of the optical lens can be reduced.

The afore-described optical framework improves the effective aperturerange. In comparison to the optical lens having an aperture stop withadjustable aperture disposed within the lens group in the conventionalskills, the optical lens of the present invention can deploy theaperture stop with adjustable aperture (that is, the second aperturestop STO2) at the outside of the lens group, and therefore thestructural components or electric control components required to be usedto mount the aperture-adjustable stop can be moved to the outside of thelens group, thereby carrying out further thinning of the optical lens.

The following is described with a package structure of the optical lensof the present invention.

Please refer to FIG. 6, which is a schematic diagram showing a packagestructure in accordance with a first embodiment of an optical lens ofthe present invention. The optical lens is packaged in an electronicdevice equipped with a photographing function and is disposed inside anexternal case 11 of the electronic device. The external case 11 has anopening 110 exposed therefrom, and light rays can thus enter the innerspace of the optical lens through the opening 110. The optical lens hasan optical system frame 15, a lens system 17, and an image recorder 18.The optical system frame 15 is made of plastic and is a fastening memberof the optical system. The lens system 17 comprises one or more lensesmounted on the optical system frame 15. The image recorder 18 canreceive the light rays transmitted from the lens system 17 and thus forman image on the image plane. The optical lens also has a transparentplate 12, a cover plate 13, a base plate 16, and one or more apertureadjusting blades 14. The base plate 16 is fastened on the optical systemframe 15 or formed by extending from the optical system frame 15. Thebase plate 16 has an opening 160 disposed at a central part thereof. Thecover plate 13 is spaced apart from the base plate 16 and is fastened tothe base plate 16 or the optical system frame 15. The cover plate 13 isa flat metal plate and is perforated to form an opening 130 at a centralpart thereof. The opening 130 of the cover plate 13 corresponds to theopening 160 of the base plate 16. The aperture adjusting blade 14 isdisposed in an accommodating space formed between the cover plate 13 andthe base plate 16. This optical lens is an aperture-adjustable opticallens. The aperture adjusting blade 14 is driven by a driver (not shown)of an aperture adjusting device (not shown). The aperture of the opticallens is altered by adjusting the position of the aperture adjustingblade 14. The transparent plate 12 is disposed at the inner side of theexternal case 11 and is disposed next to the exposed opening 110 of theexternal case 11. Also, the transparent plate 12 is attached to theoptical system frame 15. As can be seen from FIG. 6, the lens system 17,the base plate 16, the aperture adjusting blade 14, the cover plate 13,and the transparent plate 12 are sequentially arranged in order from theimage side to the object side, that is, from the image recorder 18 tothe exposed opening 110 of the external case 11.

As described above, the aperture adjusting blade 14 is disposed betweenthe lens at the most object side and the exposed opening 110 of theexternal case 11. Therefore, in comparison to that disposed between anytwo lenses, this deployment leads to have more room at the lateral sidefor accommodating its driver and leads not to affect the deployment ofother components. Further, the transparent plate 12 is fastened orattached to the optical system frame 15. Such a technical scheme canfurther prevent the dust from falling into the blade room accommodatingthe aperture adjusting blade 14.

Please refer to FIG. 7, which is a schematic diagram showing a packagestructure in accordance with a second embodiment of an optical lens ofthe present invention. In comparison to the package structure describedin the first embodiment, the present embodiment locates the base plate16 at the upper side and locates the cover plate 13 at the lower side.Screws 19 are utilized to fasten the cover plate 13 to the base plate 16or the optical system frame 15. The cover plate 13 and the base plate 16are spaced a part from each other. The aperture adjusting blade 14 isaccommodated between the cover plate 13 and the base plate 16. As can beseen from FIG. 7, the lens system 17, the cover plate 13, the apertureadjusting blade 14, the base plate 16, and the transparent plate 12 aresequentially arranged in order from the image side to the object side,that is, from the image recorder 18 to the exposed opening 110 of theexternal case 11. In such a technical scheme, the cover plate 13 ismoved to the lower side and thus the plastic material of the opticalsystem frame 15 can be partially removed for deploying a space fordisposing the screws 19, and therefore the fastening position of thescrew can be moved down. In comparison to the embodiment shown in FIG.6, this embodiment can reduce the thickness of the optical lens, andthus reduce the thickness of the device equipped with the optical lens.

The optical lens provided in the present invention will be furtherdescribed with reference to the following five embodiments taking amobile phone camera lens for example and the data adopted in therespective embodiments are listed for reference. The first embodiment isillustrated in FIGS. 1A to 1E; the second embodiment is illustrated inFIGS. 2A to 2E; the third embodiment is illustrated in FIGS. 3A to 3E;the fourth embodiment is illustrated in FIGS. 4A to 4E; and the fifthembodiment is illustrated in FIGS. 5A to 5E.

Some lenses in the optical lens of the present invention are asphericlenses. The shape of an aspheric lens may be expressed by the followingformula:

${z(r)} = {\frac{C \cdot r^{2}}{1 + \sqrt{1 - {\left( {1 + k} \right) \cdot C^{2} \cdot r^{2}}}} + {\alpha_{1}r^{2}} + {\alpha_{2}r^{4}} + {\alpha_{3}r^{6}} + {\alpha_{4}r^{8}} + {\alpha_{5}r^{10}} + {\alpha_{6}r^{12}} + {\alpha_{7}r^{14}} + {\alpha_{8}r^{16}} + {\alpha_{9}r^{18}} + {\alpha_{10}r^{20}\mspace{14mu}\ldots}}$where z represents the sag of a point on the aspheric surface at aheight h distanced to a central axis of the lens; C is a reciprocal of aparaxial curvature radius; r represents a height of a point on theaspheric surface with respect to the central axis; k is the conicconstant of the aspheric lens; and α₁, α₂, . . . , and α₁₀ are asphericsurface coefficients for even (greater than or equal to two) orderterms.

First Embodiment

FIG. 1A is a schematic diagram showing an optical structure inaccordance with a first embodiment of an optical lens of the presentinvention. The optical lens according to the first embodiment of thepresent invention comprises five pieces of lenses, which are a firstlens L1, a second lens L2, a third lens L3, a fifth lens L5, and afourth lens L4 arranged in order from the image side IMA to the objectside OBJ. The optical lens utilizes two low-dispersion lenses L2 and L3cooperating with three high-dispersion lenses L1, L4, and L5. Theframework of its refractive power is negative, positive, negative,positive, and positive in order form the image side to the object side.Specifically, the first lens L1 is a lens having negative refractivepower, and the image-side surface thereof is a concave face and has atleast a point of inflection arranged thereon. The second lens L2 is alens having positive refractive power and has a concave surface facingthe object side and a convex surface facing the image side. The thirdlens L3 is approximate to a plano-concave lens. The fifth lens L5 isapproximate to a meniscus convex lens. The fourth lens L4 is alsoapproximate to a meniscus convex lens.

The optical lens according to the first embodiment of the presentinvention also has at least two aperture stops, that is, a firstaperture stop STO1 and a second aperture stop STO2. The first aperturestop STO1 is disposed between the fourth lens L4 and the fifth lens L5and the second aperture stop STO2 is disposed at the outside of the lensat the most object side (that is, the fourth lens L4). The distance onthe optical axis from the first aperture stop STO1 to the image plane IPis SL1, the distance on the optical axis from the second aperture stopSTO2 to the image plane IP is SL2, and the distance on the optical axisfrom the object-side surface of the lens at the most object side (thatis, the fourth lens L4) to the image plane IP is TTL. The optical lensaccording to the first embodiment of the present invention satisfies thefollowing equation: 1.2<(SL1+SL2)/TTL<2.5.

As shown in Table 1 below, related data of the respective lenses of theoptical lens shown in FIG. 1A are shown in the condition that the firstaperture stop STO1 is in an active state and the second aperture stopSTO2 is in an inactive state. Table 1 shows that the focal length of theoptical lens according to the first embodiment of the present inventionis 4.363, and the refractive power for the respective lensessequentially is −6.54966, 20.2192, −4.7998, 4.1284, and 4.7496 in orderfrom L1, L2, L3, L5, and L4. In the condition that the first aperturestop STO1 is in the active state, the effective f-number of this opticalsystem is 1.8, the viewing angle is 76 degrees, and the total length ofthe optical lens is 5.21 mm. Further, in the condition that the secondaperture stop STO2 is in the active state, the effective f-number ofthis optical system is 2.4.

TABLE 1 Focal length = 4.36 mm F-number = 1.8 Maximum half angle of view= 38 Surface Radius of Thickness/ Refractive Abbe Conic Index CurvatureR (mm) Distance D (mm) Index (Nd) No. (Vd) Constant R0 Image Side R1 IRPlano 0.399847 1.5168 64.16734 0 R2 Plano 0.145 0 R3 L1 ∞ 0.5173581.535037 55.71072 −7.31959 R4 3.224664 0.687077 −37.468 R5 L2 −6.847470.316889 1.651 21.5 12.32 R6 −13.594 0.626108 −3121.95 R7 L3 −202.4720.655789 1.651 21.5 −7063.6 R8 −3.109 0.232827 0 R9 L5 −2.63506 0.0381791.79679 45.35 0 R10 −11.8121 0.530297 0 R11 STO1 ∞ 0.301989 0 R12 L44.492898 0.090208 1.58913 61.18217 0 R13 1.824606 0.67288 −0.68912 R14STO2 ∞ 0 0 R15 Object Side

Table 2 shows related data of aspheric lenses shown in Table 1.

TABLE 2 IMA Coefficient on r{circumflex over ( )} 2 Coefficient onr{circumflex over ( )} 4 Coefficient on r{circumflex over ( )} 6Coefficient on r{circumflex over ( )} 8 Coefficient on r{circumflex over( )} 10 surface 0 −0.068326463 0.022631598 −0.005707664 0.00079391 of L1Coefficient on r{circumflex over ( )} 12 Coeffieient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−5.06E−05   −5.04E−08 1.18281E−07 1.18281E−07 1.18281E−07 OBJCoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.16234125 0.063601191 −0.014359732 −0.000663867 of L1Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 200.000669046   −5.70E−06 −1.02112E−05 −1.02112E−05 −1.02112E−05 IMACoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.037355326 0.056839178 −0.047227199 0.017140171 of L2Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−0.002734669 −7.68765E−05 6.53917E−05 6.53917E−05 6.53917E−05 OBJCoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.046389552 0.054728295 −0.087083506 0.053893156 of L2Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−0.016201546 0.000158368 0.000723711 0.000723711 0.000723711 IMACoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.064112847 0.017941495 0.038314249 −0.029126597 of L3Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 200.008533352 0.002185878 −0.000751704 −0.000751704 −0.000751704 OBJCoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.072558289 −0.015939819 0.077639598 −0.013915421 of L3Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−0.02624593 0.00666058 −0.000299104 −0.000299104 −0.000299104 IMACoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.013943442 0.020475405 −0.057163629 0.023398376 of L4Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 200.012274819 −0.012467014 −0.000474625 −0.000474625 −0.000474625 OBJCoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 0.006641832 0.01166876 −0.001369296 −0.022192564 of L4Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 200.025460709 −0.011215628 0.000876751 0.000376751 0.000876751 IMACoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.013306555 −0.034459418 0.011549355 0.044164219 of L5Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−0.047675783 0.004435779 0.004355224 0.004355224 0.004355224 OBJCoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.02213491 −0.023906357 0.000935276 0.011708534 of L5Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−0.028121262 0.009003516 0.002926885 0.002926385 0.002926885

FIG. 1B is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the firstembodiment of the present invention in the condition that the firstaperture stop STO1 is in the active state and the second aperture stopSTO2 is in the inactive state. FIG. 1C is a diagram showing the opticalperformance including field curvature and distortion of the optical lensaccording to the first embodiment of the present invention in thecondition that the first aperture stop STO1 is in the inactive state andthe second aperture stop STO2 is in the active state. FIG. 1D is adiagram showing polychromatic diffraction modulation transfer function(MTF) of the optical lens according to the first embodiment of thepresent invention in the condition that the first aperture stop STO1 isin the active state and the second aperture stop STO2 is in the inactivestate. FIG. 1E is a diagram showing polychromatic diffraction modulationtransfer function of the optical lens according to the first embodimentof the present invention in the condition that the first aperture stopSTO1 is in the inactive state and the second aperture stop STO2 is inthe active state.

Second Embodiment

FIG. 2A is a schematic diagram showing an optical structure inaccordance with a second embodiment of an optical lens of the presentinvention. The optical lens according to the second embodiment of thepresent invention comprises five pieces of lenses, which are a firstlens L1, a second lens L2, a third lens L3, a fifth lens L5, and afourth lens L4 arranged in order from the image side IMA to the objectside OBJ. The optical lens utilizes one low-dispersion lens L5cooperating with four high-dispersion lenses L1, L2, L3, and L4. Theframework of its refractive power is negative, positive, positive,negative, and positive in order form the image side to the object side.Specifically, the first lens L1 is a lens having negative refractivepower, and the image-side surface thereof is a concave face and has atleast a point of inflection arranged thereon. The second lens L2 is alens having positive refractive power and has a concave surface facingthe object side and a convex surface facing the image side. The thirdlens L3 is approximate to a bi-convex lens. The fifth lens L5 isapproximate to a meniscus concave lens. The fourth lens L4 isapproximate to a bi-convex lens.

The optical lens according to the second embodiment of the presentinvention also has at least two aperture stops, that is, a firstaperture stop STO1 and a second aperture stop STO2. The first aperturestop STO1 is disposed between the fourth lens L4 and the fifth lens L5and the second aperture stop STO2 is disposed at the outside of the lensat the most object side (that is, the fourth lens L4). The distance onthe optical axis from the first aperture stop STO1 to the image plane IPis SL1, the distance on the optical axis from the second aperture stopSTO2 to the image plane IP is SL2, and the distance on the optical axisfrom the object-side surface of the lens at the most object side (thatis, the fourth lens L4) to the image plane IP is TTL. The optical lensaccording to the second embodiment of the present invention satisfiesthe following equation: 1.2<(SL1+SL2)/TTL<2.5.

As shown in Table 3 below, related data of the respective lenses of theoptical lens shown in FIG. 2A are shown in the condition that the firstaperture stop STO1 is in an active state and the second aperture stopSTO2 is in an inactive state. Table 3 shows that the focal length of theoptical lens according to the second embodiment of the present inventionis 3.29213, and the refractive power for the respective lensessequentially is −2.46914, 3.08563, 7.68479, −3.58248, and 2.46913 inorder from L1, L2, L3, L5, and L4. In the condition that the firstaperture stop STO1 is in the active state, the effective f-number ofthis optical system is 2.0, the viewing angle is 69 degrees, and thetotal length of the optical lens is 3.97 mm. Further, in the conditionthat the second aperture stop STO2 is in the active state, the effectivef-number of this optical system is 2.8.

TABLE 3 Focal length = 3.29 mm F-number = 2.0 Maximum half angle of view= 34.5 Surface Radius of Thickness/ Refractive Abbe Conic IndexCurvature R (mm) Distance D (mm) Index (Nd) No. (Vd) Constant R0 ImageSide R1 IR Plano 0.004258 1.5168 64.16734 0 R2 Plano 0.145 0 R3 L1 ∞0.88 1.5441 56.0936 −6.35903 R4 4.088057 0.378762 −133.327 R5 L2−1.05192 0.238975 1.5441 56.0936 −0.77093 R6 −2.37771 0.450713 0.179669R7 L3 −6.89504 0.464627 1.5441 56.0936 28.14493 R8 10.49814 0.39002520.16273 R9 L5 1.193641 0.364742 1.635517 23.97184 −6.08747 R10 2.6640220.215475 −35.7261 R11 STO1 ∞ 0.036573 0 R12 L4 −6.82072 −0.00473 1.544156.0936 7.335077 R13 1.644252 0.408306 0.125673 R14 STO2 ∞ 0 0 R15Object Side

Table 4 shows related data of aspheric lenses shown in Table 3.

TABLE 4 IMA Coefficient on r{circumflex over ( )} 2 Coefficient onr{circumflex over ( )} 4 Coefficient on r{circumflex over ( )} 6Coefficient on r{circumflex over ( )} 8 Coefficient on r{circumflex over( )} 10 surface 0 −0.12261161 0.049977706 −0.017665442 0.003089853 of L1Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20 −2.24E−04 0.00E+00 0 0 0 OBJ Coefficient on r{circumflex over ( )} 2Coefficient on r{circumflex over ( )} 4 Coefficient on r{circumflex over( )} 6 Coefficient on r{circumflex over ( )} 8 Coefficient onr{circumflex over ( )} 10 surface 0 −0.16359498 0.04211978 −0.001194497−0.000624809 of L1 Coefficient on r{circumflex over ( )} 12 Coefficienton r{circumflex over ( )} 14 Coefficient on r{circumflex over ( )} 16Coefficient on r{circumflex over ( )} 18 Coefficient on r{circumflexover ( )} 20 4.89916E−05 0.00E+00 0 0 0 IMA Coefficient on r{circumflexover ( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 0.24409123−0.17355054 0.070243881 −0.004203009 of L2 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 −0.000699114 0 0 0 0 OBJCoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 0.038536069 −0.11142259 0.013661737 −0.021625202 of L2Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−0.013949816 0 0 0 0 IMA Coefficient on r{circumflex over ( )} 2Coefficient on r{circumflex over ( )} 4 Coefficient on r{circumflex over( )} 6 Coefficient on r{circumflex over ( )} 8 Coefficient onr{circumflex over ( )} 10 surface 0 −0.055902836 −0.0388741830.017980386 −0.028521372 of L3 Coefficient on r{circumflex over ( )} 12Coefficient on r{circumflex over ( )} 14 Coefficient on r{circumflexover ( )} 16 Coefficient on r{circumflex over ( )} 18 Coefficient onr{circumflex over ( )} 20 0.042884788 0 0 0 0 OBJ Coefficient onr{circumflex over ( )} 2 Coefficient on r{circumflex over ( )} 4Coefficient on r{circumflex over ( )} 6 Coefficient on r{circumflex over( )} 8 Coefficient on r{circumflex over ( )} 10 surface 0 −0.051388901−0.03247322 0.15238218 −0.077963205 of L3 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 −0.013538712 0 0 0 0 IMACoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 0.13622006 −0.16886925 0.34374751 −0.58600811 of L4Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 200.4616599 0 0 0 0 OBJ Coefficient on r{circumflex over ( )} 2Coefficient on r{circumflex over ( )} 4 Coefficient on r{circumflex over( )} 6 Coefficient on r{circumflex over ( )} 8 Coefficient onr{circumflex over ( )} 10 surface 0 0.009462623 −0.012480374 −0.017720930.044712063 of L4 Coefficient on r{circumflex over ( )} 12 Coefficienton r{circumflex over ( )} 14 Coefficient on r{circumflex over ( )} 16Coefficient on r{circumflex over ( )} 18 Coefficient on r{circumflexover ( )} 20 0.013373029 0 0 0 0 IMA Coefficient on r{circumflex over( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 0.0447951390.11055632 −0.15080884 −0.070661935 of L5 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 0.095626162 0 0 0 0 OBJCoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 0.040196019 −0.090194898 0.2241962 −0.41489922 of L5Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 200.22564468 0 0 0 0

FIG. 2B is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the secondembodiment of the present invention in the condition that the firstaperture stop STO1 is in the active state and the second aperture stopSTO2 is in the inactive state. FIG. 2C is a diagram showing the opticalperformance including field curvature and distortion of the optical lensaccording to the second embodiment of the present invention in thecondition that the first aperture stop STO1 is in the inactive state andthe second aperture stop STO2 is in the active state. FIG. 2D is adiagram showing polychromatic diffraction modulation transfer function(MTF) of the optical lens according to the second embodiment of thepresent invention in the condition that the first aperture stop STO1 isin the active state and the second aperture stop STO2 is in the inactivestate. FIG. 2E is a diagram showing polychromatic diffraction modulationtransfer function of the optical lens according to the second embodimentof the present invention in the condition that the first aperture stopSTO1 is in the inactive state and the second aperture stop STO2 is inthe active state.

Third Embodiment

FIG. 3A is a schematic diagram showing an optical structure inaccordance with a third embodiment of an optical lens of the presentinvention. The optical lens according to the third embodiment of thepresent invention comprises four pieces of lenses, which are a firstlens L1, a second lens L2, a third lens L3, and a fourth lens L4arranged in order from the image side IMA to the object side OBJ. Theoptical lens utilizes one low-dispersion lens L3 cooperating with threehigh-dispersion lenses L1, L2, and L4. The framework of its refractivepower is negative, positive, negative, and positive in order form theimage side to the object side. Specifically, the first lens L1 is a lenshaving negative refractive power, and the image-side surface thereof isa concave face and has at least a point of inflection arranged thereon.The second lens L2 is a lens having positive refractive power and has aconcave surface facing the object side and a convex surface facing theimage side. The third lens L3 is approximate to a meniscus concave lens.The fourth lens L4 is approximate to a bi-convex lens.

The optical lens according to the third embodiment of the presentinvention also has at least two aperture stops, that is, a firstaperture stop STO1 and a second aperture stop STO2. The first aperturestop STO1 is disposed between the third lens L3 and the fourth lens L4and the second aperture stop STO2 is disposed at the outside of the lensat the most object side (that is, the fourth lens L4). The distance onthe optical axis from the first aperture stop STO1 to the image plane IPis SL1, the distance on the optical axis from the second aperture stopSTO2 to the image plane IP is SL2, and the distance on the optical axisfrom the object-side surface of the lens at the most object side (thatis, the fourth lens L4) to the image plane IP is TTL. The optical lensaccording to the third embodiment of the present invention satisfies thefollowing equation: 1.2<(SL1+SL2)/TTL<2.5.

As shown in Table 5 below, related data of the respective lenses of theoptical lens shown in FIG. 3A are shown in the condition that the firstaperture stop STO1 is in an active state and the second aperture stopSTO2 is in an inactive state. Table 5 shows that the focal length of theoptical lens according to the third embodiment of the present inventionis 2.224, and the refractive power for the respective lensessequentially is −1.27834, 1.15622, −2.82002, and 1.81389 in order fromL1, L2, L3, and L4. In the condition that the first aperture stop STO1is in the active state, the effective f-number of this optical system is1.8, the viewing angle is 70 degrees, and the total length of theoptical lens is 3.09 mm. Further, in the condition that the secondaperture stop STO2 is in the active state, the effective f-number ofthis optical system is 2.4.

TABLE 5 Focal length = 2.22 mm F-number = 1.8 Maximum half angle of view= 35 Surface Radius of Thickness/ Refractive Abbe Conic Index CurvatureR (mm) Distance D (mm) Index (Nd) No. (Vd) Constant R0 Image Side R1 IRPlano 0.377173 1.51633 64.14202 0 R2 Plano 0.3 0 R3 L1 0.634243 0.31.5441 56.0936 −7.33354 R4 8.27339 0.33814 −10914.7 R5 L2 −0.658790.035445 1.69003 52.75 −3.17751 R6 −2.65838 0.459447 −8.45873 R7 L31.547733 0.397755 1.632755 23.29495 −5.06099 R8 11.75026 0.229978 0 R9STO1 ∞ 0.075473 0 R10 L4 −3.3504 −0.04548 1.54 56.0936 0 R11 1.3131040.623902 0.124189 R12 STO2 ∞ 0 0 R13 Object Side

Table 6 shows related data of aspheric lenses shown in Table 5.

TABLE 6 IMA Coefficient on r{circumflex over ( )} 2 Coefficient onr{circumflex over ( )} 4 Coefficient on r{circumflex over ( )} 6Coefficient on r{circumflex over ( )} 8 Coefficient on r{circumflex over( )} 10 surface 0 −0.28029487 0.22709754 −0.15016616 0.034805119 of L1Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−0.001965392 0.003020866 −0.001881296 −0.001881296 −0.001881296 OBJCoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.28339184 0.21241489 −0.093783116 −0.033079793 of L1Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 200.017751576 −0.023275011 0.028276075 0.028276075 0.028276075 IMACoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 0.056170984 −0.75262164 1.8432287 −1.4175232 of L2 Coefficienton r{circumflex over ( )} 12 Coefficient on r{circumflex over ( )} 14Coefficient on r{circumflex over ( )} 16 Coefficient on r{circumflexover ( )} 18 Coefficient on r{circumflex over ( )} 20 −0.815433381.2821335 0 0 0 OBJ Coefficient on r{circumflex over ( )} 2 Coefficienton r{circumflex over ( )} 4 Coefficient on r{circumflex over ( )} 6Coefficient on r{circumflex over ( )} 8 Coefficient on r{circumflex over( )} 10 surface 0 0.004277422 0.014660242 −0.024193322 0.18893841 of L2Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−1.7521547 2.2681374 0 0 0 IMA Coefficient on r{circumflex over ( )} 2Coefficient on r{circumflex over ( )} 4 Coefficient on r{circumflex over( )} 6 Coefficient on r{circumflex over ( )} 8 Coefficient onr{circumflex over ( )} 10 surface 0 0.12014168 −0.039058636 −0.732534784.5037627 of L3 Coefficient on r{circumflex over ( )} 12 Coefficient onr{circumflex over ( )} 14 Coefficient on r{circumflex over ( )} 16Coefficient on r{circumflex over ( )} 18 Coefficient on r{circumflexover ( )} 20 4.6527637 0 0 0 0 OBJ Coefficient on r{circumflex over ( )}2 Coefficient on r{circumflex over ( )} 4 Coefficient on r{circumflexover ( )} 6 Coefficient on r{circumflex over ( )} 8 Coefficient onr{circumflex over ( )} 10 surface 0 −0.13331015 −1.0335069 5.14312844.7487291 of L3 Coefficient on r{circumflex over ( )} 12 Coefficient onr{circumflex over ( )} 14 Coefficient on r{circumflex over ( )} 16Coefficient on r{circumflex over ( )} 18 Coefficient on r{circumflexover ( )} 20 −1.1243573 0 0 0 0 IMA Coefficient on r{circumflex over( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 −0.015180883−1.1936464 4.9505495 −5.7629299 of L4 Coefficient on r{circumflex over( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 0 0 0 0 0 OBJ Coefficient onr{circumflex over ( )} 2 Coefficient on r{circumflex over ( )} 4Coefficient on r{circumflex over ( )} 6 Coefficient on r{circumflex over( )} 8 Coefficient on r{circumflex over ( )} 10 surface 0 −0.047670449−0.1274337 0.12082106 −0.45177542 of L4 Coefficient on r{circumflex over( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 0 0 0 0 0

FIG. 3B is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the thirdembodiment of the present invention in the condition that the firstaperture stop STO1 is in the active state and the second aperture stopSTO2 is in the inactive state. FIG. 3C is a diagram showing the opticalperformance including field curvature and distortion of the optical lensaccording to the third embodiment of the present invention in thecondition that the first aperture stop STO1 is in the inactive state andthe second aperture stop STO2 is in the active state. FIG. 3D is adiagram showing polychromatic diffraction modulation transfer function(MTF) of the optical lens according to the third embodiment of thepresent invention in the condition that the first aperture stop STO1 isin the active state and the second aperture stop STO2 is in the inactivestate. FIG. 3E is a diagram showing polychromatic diffraction modulationtransfer function of the optical lens according to the third embodimentof the present invention in the condition that the first aperture stopSTO1 is in the inactive state and the second aperture stop STO2 is inthe active state.

Fourth Embodiment

FIG. 4A is a schematic diagram showing an optical structure inaccordance with a fourth embodiment of an optical lens of the presentinvention. The optical lens according to the fourth embodiment of thepresent invention comprises four pieces of lenses, which are a firstlens L1, a second lens L2, a third lens L3, and a fourth lens L4arranged in order from the image side IMA to the object side OBJ. Theoptical lens utilizes one low-dispersion lens L2 cooperating with threehigh-dispersion lenses L1, L3, and L4. The framework of its refractivepower is negative, negative, positive, and positive in order form theimage side to the object side. Specifically, the first lens L1 is a lenshaving negative refractive power, and the image-side surface thereof isa concave face and has at least a point of inflection arranged thereon.The second lens L2 is a lens having negative refractive power and has aconcave surface facing the object side and a convex surface facing theimage side. The third lens L3 is approximate to a meniscus convex lensand has a concave surface facing the object side and a convex surfacefacing the image side. The fourth lens L4 is approximate to a meniscusconvex lens.

The optical lens according to the fourth embodiment of the presentinvention also has at least two aperture stops, that is, a firstaperture stop STO1 and a second aperture stop STO2. The first aperturestop STO1 is disposed between the third lens L3 and the fourth lens L4and the second aperture stop STO2 is disposed at the outside of the lensat the most object side (that is, the fourth lens L4). The distance onthe optical axis from the first aperture stop STO1 to the image plane IPis SL1, the distance on the optical axis from the second aperture stopSTO2 to the image plane IP is SL2, and the distance on the optical axisfrom the object-side surface of the lens at the most object side (thatis, the fourth lens L4) to the image plane IP is TTL. The optical lensaccording to the third embodiment of the present invention satisfies thefollowing equation: 1.2<(SL1+SL2)/TTL<2.5.

As shown in Table 7 below, related data of the respective lenses of theoptical lens shown in FIG. 4A are shown in the condition that the firstaperture stop STO1 is in an active state and the second aperture stopSTO2 is in an inactive state. Table 7 shows that the focal length of theoptical lens according to the fourth embodiment of the present inventionis 2.3182, and the refractive power for the respective lensessequentially is −14.3533, −4.61481, 2.07924, and 3.14393 in order fromL1, L2, L3, and L4. In the condition that the first aperture stop STO1is in the active state, the effective f-number of this optical system is1.8, the viewing angle is 89 degrees, and the total length of theoptical lens is 3.409 mm. Further, in the condition that the secondaperture stop STO2 is in the active state, the effective f-number ofthis optical system is 2.8.

TABLE 7 Focal length = 2.318 mm F-number = 1.8 Maximum half angle ofview = 44.5 Surface Radius of Thickness/ Refractive Abbe Conic IndexCurvature R (mm) Distance D (mm) Index (Nd) No. (Vd) Constant R0 ImageSide R1 IR Plano 0.105362 1.51633 64.14202 0 R2 Plano 0.21 0 R3 L10.898954 0.6844 1.5441 56.0936 −2.90282 R4 1.195782 0.452062 −0.44492 R5L2 −1.26429 0.202173 1.650958 21.51361 0.051651 R6 −0.76452 0.455948−0.24406 R7 L3 −1.19373 0.081371 1.755 51.2 0.037002 R8 4.0376 0.4999495.994392 R9 STO1 ∞ 0.35304 0 R10 L4 8.735552 0.003026 1.755 51.2 0 R111.905175 0.362252 2.440844 R12 STO2 ∞ 0 0 R13 Object Side

Table 8 shows related data of aspheric lenses shown in Table 7.

TABLE 8 IMA Coefficient on r{circumflex over ( )} 2 Coefficient onr{circumflex over ( )} 4 Coefficient on r{circumflex over ( )} 6Coefficient on r{circumflex over ( )} 8 Coefficient on r{circumflex over( )} 10 surface 0 −0.23128355 0.14175378 −0.067994162 0.0213542 of L1Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−0.004568351 0.000508655 −1.12562E−05 −1.12562E−05 −1.12562E−05 OBJCoefficient on r{circumflex over ( )} 2 Coefficient on r{circumflex over( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.52650509 0.25194 −0.17353961 0.14660685 of L1 Coefficienton r{circumflex over ( )} 12 Coefficient on r{circumflex over ( )} 14Coefficient on r{circumflex over ( )} 16 Coefficient on r{circumflexover ( )} 18 Coefficient on r{circumflex over ( )} 20 −0.101832050.039677909 −0.006161127 −0.006161127 −0.006161127 IMA Coefficient onr{circumflex over ( )} 2 Coefficient on r{circumflex over ( )} 4Coefficient on r{circumflex over ( )} 6 Coefficient on r{circumflex over( )} 8 Coefficient on r{circumflex over ( )} 10 surface 0 0.270109320.06650994 −0.32301541 0.77365395 of L2 Coefficient on r{circumflex over( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 −0.94713717 0.59387626−0.14295684 −0.14295684 −0.14295684 OBJ Coefficient on r{circumflex over( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 0.66898512−0.61306349 1.4858343 −1.342644 of L2 Coefficient on r{circumflex over( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 2.9844358 −6.412385 4.68911194.6891119 4.6891119 IMA Coefficient on r{circumflex over ( )} 2Coefficient on r{circumflex over ( )} 4 Coefficient on r{circumflex over( )} 6 Coefficient on r{circumflex over ( )} 8 Coefficient onr{circumflex over ( )} 10 surface 0 −0.14982592 0.078819059 −0.635348562.5712369 of L3 Coefficient on r{circumflex over ( )} 12 Coefficient onr{circumflex over ( )} 14 Coefficient on r{circumflex over ( )} 16Coefficient on r{circumflex over ( )} 18 Coefficient on r{circumflexover ( )} 20 −3.7370466 1.9102048 −0.30854624 −0.30854624 −0.30854624OBJ Coefficient on r{circumflex over ( )} 2 Coefficient on r{circumflexover ( )} 4 Coefficient on r{circumflex over ( )} 6 Coefficient onr{circumflex over ( )} 8 Coefficient on r{circumflex over ( )} 10surface 0 −0.28823379 −0.22965413 0.14621395 −1.3892127 of L3Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 20−0.77150298 17.474959 −20.688299 −20.688299 −20.688299 IMA Coefficienton r{circumflex over ( )} 2 Coefficient on r{circumflex over ( )} 4Coefficient on r{circumflex over ( )} 6 Coefficient on r{circumflex over( )} 8 Coefficient on r{circumflex over ( )} 10 surface 0 −0.1787120.39455994 −2.7937285 1.5267098 of L4 Coefficient on r{circumflex over( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 28.838141 −82.831787 66.3471766.34717 66.34717 OBJ Coefficient on r{circumflex over ( )} 2Coefficient on r{circumflex over ( )} 4 Coefficient on r{circumflex over( )} 6 Coefficient on r{circumflex over ( )} 8 Coefficient onr{circumflex over ( )} 10 surface 0 −0.087825582 −0.23623031 0.25832584−0.042191405 of L4 Coefficient on r{circumflex over ( )} 12 Coefficienton r{circumflex over ( )} 14 Coefficient on r{circumflex over ( )} 16Coefficient on r{circumflex over ( )} 18 Coefficient on r{circumflexover ( )} 20 4.1396749 10.902824 −9.0782311 −9.0782311 −9.0782311

FIG. 4B is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the fourthembodiment of the present invention in the condition that the firstaperture stop STO1 is in the active state and the second aperture stopSTO2 is in the inactive state. FIG. 4C is a diagram showing the opticalperformance including field curvature and distortion of the optical lensaccording to the fourth embodiment of the present invention in thecondition that the first aperture stop STO1 is in the inactive state andthe second aperture stop STO2 is in the active state. FIG. 4D is adiagram showing polychromatic diffraction modulation transfer function(MTF) of the optical lens according to the fourth embodiment of thepresent invention in the condition that the first aperture stop STO1 isin the active state and the second aperture stop STO2 is in the inactivestate. FIG. 4E is a diagram showing polychromatic diffraction modulationtransfer function of the optical lens according to the fourth embodimentof the present invention in the condition that the first aperture stopSTO1 is in the inactive state and the second aperture stop STO2 is inthe active state.

Fifth Embodiment

FIG. 5A is a schematic diagram showing an optical structure inaccordance with a fifth embodiment of an optical lens of the presentinvention. The optical lens according to the fifth embodiment of thepresent invention comprises five pieces of lenses, which are a firstlens L1, a second lens L2, a third lens L3, a fifth lens L5, and afourth lens L4 arranged in order from the image side IMA to the objectside OBJ. The optical lens utilizes two low-dispersion lenses L2 and L3cooperating with three high-dispersion lenses L1, L4, and L5. Theframework of its refractive power is negative, positive, negative,positive, and positive in order form the image side to the object side.Specifically, the first lens L1 is a lens having negative refractivepower, and the image-side surface thereof is a concave face and has atleast a point of inflection arranged thereon. The second lens L2 is alens having positive refractive power and has a concave surface facingthe object side and a convex surface facing the image side. The thirdlens L3 is approximate to a meniscus concave lens. The fifth lens L5 isapproximate to a meniscus convex lens. The fourth lens L4 is alsoapproximate to a meniscus convex lens.

The optical lens according to the fifth embodiment of the presentinvention also has at least two aperture stops, that is, a firstaperture stop STO1 and a second aperture stop STO2. The first aperturestop STO1 is disposed between the fourth lens L4 and the fifth lens L5and the second aperture stop STO2 is disposed at the outside of the lensat the most object side (that is, the fourth lens L4). The distance onthe optical axis from the first aperture stop STO1 to the image plane IPis SL1, the distance on the optical axis from the second aperture stopSTO2 to the image plane IP is SL2, and the distance on the optical axisfrom the object-side surface of the lens at the most object side (thatis, the fourth lens L4) to the image plane IP is TTL. The optical lensaccording to the first embodiment of the present invention satisfies thefollowing equation: 1.2<(SL1+SL2)/TTL<2.5.

As shown in Table 9 below, related data of the respective lenses of theoptical lens shown in FIG. 5A are shown in the condition that the firstaperture stop STO1 is in an active state and the second aperture stopSTO2 is in an inactive state. Table 9 shows that the focal length of theoptical lens according to the fifth embodiment of the present inventionis 4.156, and the refractive power for the respective lensessequentially is −7.5603, 17.4728, −4.8351, 4.09945, and 4.87028 in orderfrom L1, L2, L3, L5, and L4. In the condition that the first aperturestop STO1 is in the active state, the effective f-number of this opticalsystem is 1.6, the viewing angle is 79 degrees, and the total length ofthe optical lens is 5.19 mm. Further, in the condition that the secondaperture stop STO2 is in the active state, the effective f-number ofthis optical system is 2.6.

TABLE 9 Focal length = 4.15 mm F-number = 1.6 Maximum half angle of view= 39.5 Surface Radius of Thickness/ Refractive Abbe Conic IndexCurvature R (mm) Distance D (mm) Index (Nd) No. (Vd) Constant R0 ImageSide R1 IR Plano 0.11413 1.5168 64.16734 0 R2 Plano 0.145 0 R3 L1 ∞ 0.81.535037 55.71072 −5.44208 R4 3.015938 0.745032 −17.1337 R5 L2 −6.78720.313655 1.651 21.5 12.06767 R6 −16.0254 0.554647 −2555.19 R7 L3−100.075 0.591153 1.651 21.5 −11896 R8 −3.08129 0.232166 0 R9 L5−2.76701 0.038179 1.79679 45.35 0 R10 −15.7774 0.641223 0 R11 STO1 ∞0.345203 0 R12 L4 4.659665 0.078218 1.59 61.18 0 R13 1.870937 0.598805−0.69405 R14 STO2 ∞ 0 0 R15 Object Side

Table 10 shows related data of aspheric lenses shown in Table 9.

TABLE 10 IMA Coefficient on r{circumflex over ( )} 2 Coefficient onr{circumflex over ( )} 4 Coefficient on r{circumflex over ( )} 6Coefficient on r{circumflex over ( )} 8 Coefficient on r{circumflex over( )} 10 surface 0 −0.071190542 0.024244691 −0.00591398 0.000790785 of L1Coefficient on r{circumflex over ( )} 12 Coefficient on r{circumflexover ( )} 14 Coefficient on r{circumflex over ( )} 16 Coefficient onr{circumflex over ( )} 18 Coefficient on r{circumflex over ( )} 204.92E−05   3.19E−08 9.62427E−08 9.62427E−08 9.62427E−08 OBJ Coefficienton r{circumflex over ( )} 2 Coefficient on r{circumflex over ( )} 4Coefficient on r{circumflex over ( )} 6 Coefficient on r{circumflex over( )} 8 Coefficient on r{circumflex over ( )} 10 surface 0 −0.165006060.062901685 −0.014461672 −0.000675361 of L1 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 0.000665084   −5.40E−06−9.74299E−06 −9.74299E−06 −9.74299E−06 IMA Coefficient on r{circumflexover ( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 −0.036443240.056433494 −0.048174107 0.01705914 of L2 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 −0.002686547 −6.06425E−056.32451E−05 6.32451E−05 6.32451E−05 OBJ Coefficient on r{circumflex over( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 −0.0358793660.049041986 −0.087187532 0.05414856 of L2 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 −0.016025378 0.0001790430.000657297 0.000657297 0.000657297 IMA Coefficient on r{circumflex over( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 −0.0618339680.014413759 0.036786997 −0.029378927 of L3 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 0.008084592 0.0017970250.000727565 −0.000727565 −0.000727565 OBJ Coefficient on r{circumflexover ( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 −0.07261039−0.018200106 0.075646828 −0.013022632 of L3 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 −0.024606296 0.007762861−0.000321085 −0.000321085 −0.000321085 IMA Coefficient on r{circumflexover ( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 −0.0158733470.023847742 −0.053177251 0.022204617 of L4 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 0.007014824 −0.0158518210.005477248 0.005477248 0.005477248 OBJ Coefficient on r{circumflex over( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 0.0064655540.01071186 −0.00123002 −0.022193926 of L4 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 0.025220379 −0.0114825420.000917697 0.000917697 0.000917697 IMA Coefficient on r{circumflex over( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 −0.017238977−0.037305922 0.010955635 0.046272346 of L5 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 −0.044312667 0.0062891620.002419004 0.002419004 0.002419004 OBJ Coefficient on r{circumflex over( )} 2 Coefficient on r{circumflex over ( )} 4 Coefficient onr{circumflex over ( )} 6 Coefficient on r{circumflex over ( )} 8Coefficient on r{circumflex over ( )} 10 surface 0 −0.019858833−0.025689834 0.000320202 0.014439705 of L5 Coefficient on r{circumflexover ( )} 12 Coefficient on r{circumflex over ( )} 14 Coefficient onr{circumflex over ( )} 16 Coefficient on r{circumflex over ( )} 18Coefficient on r{circumflex over ( )} 20 −0.025103433 0.0095977250.000453701 0.000453701 0.000453701

FIG. 5B is a diagram showing the optical performance including fieldcurvature and distortion of the optical lens according to the fifthembodiment of the present invention in the condition that the firstaperture stop STO1 is in the active state and the second aperture stopSTO2 is in the inactive state. FIG. 5C is a diagram showing the opticalperformance including field curvature and distortion of the optical lensaccording to the fifth embodiment of the present invention in thecondition that the first aperture stop STO1 is in the inactive state andthe second aperture stop STO2 is in the active state. FIG. 5D is adiagram showing polychromatic diffraction modulation transfer function(MTF) of the optical lens according to the fifth embodiment of thepresent invention in the condition that the first aperture stop STO1 isin the active state and the second aperture stop STO2 is in the inactivestate. FIG. 5E is a diagram showing polychromatic diffraction modulationtransfer function of the optical lens according to the fifth embodimentof the present invention in the condition that the first aperture stopSTO1 is in the inactive state and the second aperture stop STO2 is inthe active state.

While the preferred embodiments of the present invention have beenillustrated and described in detail, various modifications andalterations can be made by persons skilled in this art. The embodimentof the present invention is therefore described in an illustrative butnot restrictive sense. It is intended that the present invention shouldnot be limited to the particular forms as illustrated, and that allmodifications and alterations which maintain the spirit and realm of thepresent invention are within the scope as defined in the appendedclaims.

What is claimed is:
 1. An optical lens, which makes object light raystransmit from an object side to an image side on an optical axis andform an image on an image plane, said optical lens comprising: a lensgroup establishing the optical axis, comprising a first lens and asecond lens arranged in order from the image side to the object side;and a first aperture stop and a second aperture stop separately locatedon the optical axis, wherein the first lens has an image-side surfacewhich is a concave face and has a point of inflection arranged thereon;wherein the second lens comprises a concave surface facing the objectside and a convex surface facing the image side; and wherein the opticallens satisfies the following equation:1.2<(SL1+SL2)/TTL<2.5, where SL1 is a distance on the optical axis fromthe first aperture stop to the image plane; SL2 is a distance on theoptical axis from the second aperture stop to the image plane; and TTLis a distance on the optical axis from an object-side surface of a lensof the lens group at the most object side to the image plane.
 2. Theoptical lens according to claim 1, wherein the first lens has negativerefractive power.
 3. The optical lens according to claim 2, wherein thelens group comprises the first lens, the second lens, a third lens, anda fourth lens arranged in order from the image side to the object side,and the fourth lens has positive refractive power.
 4. The optical lensaccording to claim 3, wherein the lens group further comprises a fifthlens disposed between the third lens and the fourth lens, and the secondlens has positive refractive power and at least one of the third lensand the fifth lens has positive refractive power.
 5. The optical lensaccording to claim 4, wherein the fourth lens and the fifth lens aremeniscus convex lenses, the third lens is a plano-concave lens.
 6. Theoptical lens according to claim 5, wherein the second aperture stop isdisposed between the object side and a lens of the lens group at themost object side and the first aperture stop is disposed between theimage side and the lens of the lens group at the most object side.
 7. Anoptical lens, which makes object light rays transmit from an object sideto an image side on an optical axis and form an image on an image plane,said optical lens comprising: a lens group establishing the opticalaxis, comprising a first lens and a second lens arranged in order fromthe image side to the object side; and a first aperture stop and asecond aperture stop separately located on the optical axis, wherein thefirst lens has an image-side surface which is a concave face and has apoint of inflection arranged thereon; wherein the second lens comprisesa concave surface facing the object side and a convex surface facing theimage side; and wherein the optical lens further comprises: an opticalsystem frame configured to mount the lens group thereon; a base platefastened on the optical system frame or formed by extending from theoptical system frame; a cover plate spaced apart from the base plate andfastened to the base plate; one or more aperture adjusting bladesincluded in the second aperture, the aperture of the second aperturestop being altered by adjusting the aperture adjusting blade, theaperture adjusting blade being disposed between the cover plate and thebase plate; and a transparent plate attached to the optical systemframe; wherein the lens group, the base plate, the aperture adjustingblade, the cover plate, and the transparent plate are arranged in orderfrom the image side to the object side.
 8. The optical lens according toclaim 2, further comprising: an optical system frame configured to mountthe lens group thereon; a base plate fastened on the optical systemframe or formed by extending from the optical system frame; a coverplate spaced apart from the base plate and fastened to the base plate;one or more aperture adjusting blades included in the second aperture,the aperture of the second aperture stop being altered by adjusting theaperture adjusting blade, the aperture adjusting blade being disposedbetween the cover plate and the base plate; and a transparent plateattached to the optical system frame; wherein the lens group, the baseplate, the aperture adjusting blade, the cover plate, and thetransparent plate are arranged in order from the image side to theobject side.
 9. The optical lens according to claim 3, furthercomprising: an optical system frame configured to mount the lens groupthereon; a base plate fastened on the optical system frame or formed byextending from the optical system frame; a cover plate spaced apart fromthe base plate and fastened to the base plate; one or more apertureadjusting blades included in the second aperture, the aperture of thesecond aperture stop being altered by adjusting the aperture adjustingblade, the aperture adjusting blade being disposed between the coverplate and the base plate; and a transparent plate attached to theoptical system frame; wherein the lens group, the base plate, theaperture adjusting blade, the cover plate, and the transparent plate arearranged in order from the image side to the object side.
 10. Theoptical lens according to claim 4, further comprising: an optical systemframe configured to mount the lens group thereon; a base plate fastenedon the optical system frame or formed by extending from the opticalsystem frame; a cover plate spaced apart from the base plate andfastened to the base plate; one or more aperture adjusting bladesincluded in the second aperture, the aperture of the second aperturestop being altered by adjusting the aperture adjusting blade, theaperture adjusting blade being disposed between the cover plate and thebase plate; and a transparent plate attached to the optical systemframe; wherein the lens group, the base plate, the aperture adjustingblade, the cover plate, and the transparent plate are arranged in orderfrom the image side to the object side.
 11. The optical lens accordingto claim 5, further comprising: an optical system frame configured tomount the lens group thereon; a base plate fastened on the opticalsystem frame or formed by extending from the optical system frame; acover plate spaced apart from the base plate and fastened to the baseplate; one or more aperture adjusting blades included in the secondaperture, the aperture of the second aperture stop being altered byadjusting the aperture adjusting blade, the aperture adjusting bladebeing disposed between the cover plate and the base plate; and atransparent plate attached to the optical system frame; wherein the lensgroup, the base plate, the aperture adjusting blade, the cover plate,and the transparent plate are arranged in order from the image side tothe object side.
 12. The optical lens according to claim 7, wherein thesecond aperture stop is an aperture stop with adjustable aperture, andthe aperture of the first aperture stop is greater than that of thesecond aperture stop when the aperture of the second aperture stop isadjusted to be in an active state.
 13. An optical lens, which makesobject light rays transmit from an object side to an image side on anoptical axis and form an image on an image plane, said optical lenscomprising: a lens group establishing the optical axis; a first aperturestop disposed within the lens group; and a second aperture stop disposedat the object side outside the lens group, wherein the second aperturestop is an aperture stop with adjustable aperture, and the aperture ofthe first aperture stop is greater than that of the second aperture stopwhen the aperture of the second aperture stop is adjusted to be in anactive state, wherein the optical lens satisfies the following equation:1.2<(SL1+SL2)/TTL<2.5, where SL1 is a distance on the optical axis fromthe first aperture stop to the image plane; SL2 is a distance on theoptical axis from the second aperture stop to the image plane; and TTLis a distance on the optical axis from an object-side surface of a lensof the lens group at the most object side to the image plane.
 14. Theoptical lens according to claim 13, wherein the lens group comprises afirst lens, a second lens, a third lens, and a fourth lens arranged inorder from the image side to the object side, and the refractive powerof the first lens to the fourth lens sequentially are negative,positive, negative, and positive, or negative, negative, positive, andpositive, or negative, positive, positive, and positive.
 15. The opticallens according to claim 14, wherein the lens group further comprises afifth lens disposed between the third lens and the fourth lens, and therefractive power of the lenses of the lens group sequentially arenegative, positive, negative, positive, and positive, or negative,positive, positive, negative, and positive in order from the image sideto the object side, and wherein the first aperture stop is disposedbetween the third lens and fourth lens or between the fourth lens andthe fifth lens.
 16. The optical lens according to claim 13, furthercomprising: an optical system frame configured to mount the lens groupthereon; a base plate having a first opening, the base plate beingfastened on the optical system frame or formed by extending from theoptical system frame; a cover plate having a second opening, the coverplate being spaced apart from the base plate and fastened to the baseplate through a screw; and one or more aperture adjusting bladesincluded in the second aperture, the aperture of the second aperturestop being altered by adjusting the aperture adjusting blade, theaperture adjusting blade being disposed between the cover plate and thebase plate; wherein the lens group, the cover plate, the apertureadjusting blade, and the base plate are arranged in order from the imageside to the object side.
 17. The optical lens according to claim 13,wherein the fourth lens and the fifth lens are meniscus convex lenses,the third lens is a plano-concave lens, and the second lens comprises anobject-side concave surface and an image-side convex surface.